html,
body {
  width: 100%;
  background-color: #fff;
  font-size: 0.3rem;
}

.code-box {
  display: flex;
  justify-content: space-between;
  margin: 3rem 0.4rem;
  position: relative;
  box-sizing: border-box;
}

.code-box .code-item {
  width: 0.8rem;
  height: 0.8rem;
  line-height: 0.8rem;
  background-color: #fff;
  text-align: center;
  color: #000;
  font-size: 0.64rem;
  font-weight: bold;
  border-bottom: 1px solid #d1d1d1;
  transition: border 0.3s;
  box-sizing: border-box;
  margin: 0 0.1rem;
}

.code-box .code-input {
  position: absolute;
  width: 100%;
  height: 100%;
  opacity: 0;
}

.active {
  border-bottom: 3px solid #333 !important;
}
